A diaper (in North America) or nappy (in the United Kingdom, Australia, many Commonwealth countries and Ireland) is a sponge-like garment which people wear who are incapable of controlling their bladder or bowel movements, or are unable or unwilling to use a toilet. When diapers become full and can no longer hold any more waste, they require changing; this process is often performed by a secondary person such as a parent or caregiver. Failure to change a diaper on a regular enough basis can result in diaper rash.

Diapers have been worn throughout human history, and made of cloth or disposable materials. Whereas cloth diapers are composed of layers of fabric such as microfiber and can be washed and reused multiple times, disposable diapers contain absorbent chemicals and are thrown away after use. The decision to use cloth or disposable diapers is a controversial one, owing to issues ranging from convenience, health, cost, and their effect on the environment. Currently, disposable diapers are the most commonly used, with Pampers, Luvs, and Huggies being some well-known brands in the industry. Plastic pants can be worn over diapers to avoid leaks, but with modern cloth diapers, this is no longer necessary.

Diapers are primarily worn by children who are not yet potty trained or suffer from bedwetting. However, they can also be used by adults who suffer from incontinence or in certain circumstances where access to a toilet is unavailable. These can include the elderly, those with a physical or mentaldisability, and people working in extreme conditions such as astronauts. It is not uncommon for people to wear diapers under dry suits. Diapers are usually worn out of necessity rather than choice, although there are exceptions; people such as infantilists and diaper fetishists wear diapers recreationally for comfort, emotional fulfillment, or sexual gratification. Terms such as "incontinence pads" can be used to refer to adult diapers.

An alternative to infant diapers is infant potty training or elimination communication, a technique that involves sound association, learning an infant’s body language, and reacting quickly enough to reach a suitable spot for elimination [1].

The word diaper originally referred to the type of cloth rather than its use; "diaper" was the term for a pattern of small repeated geometric shapes, and later came to describe a white cotton or linen fabric with this pattern[3]. The first cloth diapers consisted of a special type of soft tissue sheet, cut into geometric shapes. This type of pattern was called diapering and eventually gave its name to the cloth used to make diapers and then to the diaper itself. This usage stuck in the United States and Canada, but in Britain the word "nappy" took its place. Most sources believe nappy is a diminutive form of the word napkin[4].

Diapering, or clothing children not yet toilet trained is as old as human history. In some countries with warmer climates, babies were kept naked and mothers tried to anticipate their bowel movements so as to avoid mess near their living areas.

In the 19th century, the modern diaper began to take shape and children in Europe and North America were being diapered using cotton material, held in place with a safety pin. Cloth diapers were first mass produced in 1887 by Maria Allen in the United States.

In the 20th century, the disposable diaper gradually evolved through the inventions of several different people. In 1942, a Swedish paper company known as Pauliström created the first disposable diaper using sheets of tissue placed inside rubber pants. Four years later, an Americanhousewife in Westport, Connecticut, Marion Donovan, developed a waterproof diaper cover known as the "Boater" using a sheet of plastic from a shower curtain; she was granted four patents for her invention, including the use of plastic snaps as opposed to safety pins[5]. In 1947, a man named George M. Schroder invented the first diaper with disposable nonwoven fabric.[6] Disposable diapers were introduced to the US in 1949 by Johnson & Johnson. One of their scientists, Dennis C. Holtman, was especially invaluable inventing these materials. During the 1950s, companies such as Kendall, Parke-Davis, Playtex, and Molnlycke entered the disposable diaper market. In 1956, Procter & Gamble began researching disposable diapers. Victor Mills, along with his project group including William Dehaas, both men who worked for the company, invented what would be trademarked "Pampers". Presented to Fred Wells as project p-57 (this was the plane Wells had taught American pilots to fly during WWII), Mills stated, "This one will fly." Although Pampers were conceptualized in 1959, the diapers themselves were not launched into the market until 1961[7].

Over the next few decades, the disposable diaper industry boomed and the competition between Procter & Gamble's Pampers and Kimberly Clark's Huggies resulted in lower prices and drastic changes to diaper design. Several improvements were made, such as the introduction of refastenable tapes, the "hourglass shape" so as to reduce bulk at the crotch area, and the 1984 introduction of super-absorbent material from polymers known as sodium polyacrylate that were originally developed in 1966.[8][9]

Since their introduction several decades ago, product innovations include the use of superabsorbent polymers, resealable tapes, and elasticised waist bands. They are now much thinner and much more absorbent. The product range has more recently been extended into children's toilet training phase with the introduction of training pants and pant diapers.

Modern disposable baby diapers and incontinence products have a layered construction[10], which allows the transfer and distribution of urine to an absorbent core structure where it is locked in. Basic layers are an outer shell of breathable polyethylene film or a nonwoven and film composite which prevents wetness and soil transfer, an inner absorbent layer of a mixture of cellulose pulp and superabsorbent polymers for wetness, and a layer nearest the skin of nonwoven material with a distribution layer directly beneath which transfers wetness to the absorbent layer.

Other common features of disposable diapers include one or more pairs of either adhesive or velcro tapes to keep the diaper securely fastened. Some diapers have tapes which are refastenable to allow adjusting of fit or reapplication following confirmation of an as yet unsoiled diaper. Elasticized fabric around the leg and waist areas aid in fitting and in containing urine or stool which has not been absorbed. Some diapers lines now commonly include wetness indicators, in which a chemical included in the fabric of the diaper changes color in the presence of moisture to alert the carer or user that the diaper is wet.[11] A disposable diaper may also include an inner fabric designed to hold moisture against the skin for a brief period before absorption to alert a toilet training or bedwetting user that they have urinated. Most materials in the diaper are held together with the use of a hot melt adhesive which is applied in spray form or multi lines, an elastic hot melt is also used to help with pad integrity when the diaper is wet.

Some disposable diapers include fragrances, lotions or essential oils in order to help mask the scent of a soiled diaper or to protect the skin. Care of disposable diapers is minimal, and primarily consists of keeping them in a dry place before use, with proper disposal in a garbage receptacle upon soiling. Stool is supposed to be deposited in the toilet, but is generally put in the garbage with the rest of the diaper.

Cloth diapers are reusable and can be made from natural fibers, manmade materials, or a combination of both. They are often made from industrial cotton which may be bleached white or left the fiber’s natural color. Other natural fiber cloth materials include wool, bamboo, and unbleached hemp. Manmade materials such as an internal absorbent layer of microfiber toweling or an external waterproof layer of polyurethane laminate (PUL) may be used. Polyester fleece and faux suedecloth are often used inside cloth diapers as a "stay-dry" wicking liner because of the non-absorbent properties of those synthetic fibers.

Traditionally, cloth diapers consisted of a folded square or rectangle of cloth, fastened with safety pins. Modern cloth diapers come in a host of shapes, including preformed cloth diapers, all-in-one diapers with waterproof exteriors, and pocket or "stuffable" diapers, which consist of a water-resistant outer shell sewn with an opening for insertion of absorbent material inserts[13]. Closure methods include snap closures and hook and loop fasteners (such as Velcro).

Cloth diapers require dry storage as well, and equipment and supplies for cleaning. Cloth diapers place less stress on landfills as compared to single-use disposable diapers, but also require washing in water with detergent to be properly cleaned. The method of "dry-pailing" after removal of solid waste and washing on a cold or warm wash removes most bacteria. Sun exposure will kill any remainder and usually resolves any staining issues. As an alternative to at-home cleaning, some locations have a fee-based cloth diapering service that delivers clean diapers and picks up soiled ones, while parents in more rural areas often find that they must clean diapers using their own cleaning facilities.

Some brands seek to combine cloth and disposable diapers. Generally, these hybrids are cloth diapers with a disposable inner layer.

Cloth diaper-wearing children go through about 6,000 diaper changes. If thrown into a landfill, cotton diapers decompose within six months.[citation needed] Since disposable diapers are discarded after a single use, usage of disposable diapers increases the burden on landfill sites, and increased environmental awareness has led to a growth in campaigns for parents to use reusable alternatives such as cloth or hybrid diapers. An estimated 27.4 billion disposable diapers are used each year in the US, resulting in a possible 3.4 million tons of used diapers adding to landfills each year.[14]

The environmental impact of cloth as compared to disposable diapers has been studied several times. In one cradle-to-grave study sponsored by the National Association of Diaper Services (NADS) and conducted by Carl Lehrburger and colleagues, results found that disposable diapers produce seven times more solid waste when discarded and three times more waste in the manufacturing process.[citation needed] In addition, effluents from the plastic, pulp, and paper industries are far more hazardous than those from the cotton-growing and -manufacturing processes. Single-use diapers consume less water than reusables laundered at home, but more than those sent to a commercial diaper service. According to industry data from Franklin Associates and the American Petroleum Institute, 3.5 billion gallons of oil are used to produce the 18 million throwaway diapers that end up in landfills each year. Washing cloth diapers at home uses 50 to 70 gallons of water every three days, which is roughly equivalent to flushing the toilet five times a day, unless the user has a high-efficiency washing machine. An average diaper service puts its diapers through an average of 13 water changes, but uses less water and energy per diaper than one laundry load at home.[15]

Other studies have indicated that reusable diapers are more damaging to the environment [16]. The United Kingdom based Women's Environmental Network[citation needed] has claimed that all such studies promoted there were directly funded or commissioned by disposable diaper companies. In one instance in July 1991, such companies withdrew their claims amid pressure from the press upon the release of analysis done by The Landbank Consultancy, an independent environmental agency. The Landbank Report of January 1991[citation needed] concluded that, compared to cloth diapers, throwaway diapers use 20 times more raw materials, three times more energy, twice as much water, and generate 60 times more waste.

In October 2008, "An updated lifecycle assessment study for disposable and reusable nappies" by the UK Environment Agency and Department for Environment, Food and Rural Affairs stated that reusable diapers can cause significantly less (up to 40 per cent) or significantly more damage to the environment than disposable ones, depending mostly on how parents wash and dry them. The "baseline scenario" showed that the difference in green-house emissions was insignificant (in fact, disposables even scored slightly better). However, much better results (emission cuts of up to 40 per cent) could be achieved by using reusable diapers more rationally. "The report shows that, in contrast to the use of disposable nappies, it is consumers’ behaviour after purchase that determines most of the impacts from reusable nappies. Cloth nappy users can reduce their environmental impacts by:

There are variations in the care of cloth diapers that can account for different measures of environmental impact. For example, using a cloth diaper laundering service involves additional pollution from the vehicle that picks up and drops off deliveries. Yet such a service uses less water per diaper in the laundering process.[18] Some people who launder cloth diapers at home wash each load twice, considering the first wash a "prewash", and thus doubling the energy and water usage from laundering. Cloth diapers are most commonly made of cotton, which is generally considered an environmentally wasteful crop to grow. "Conventional cotton is one of the most chemically-dependent crops, sucking up 10% of all agricultural chemicals and 25% of insecticides on 3% of our arable land; that's more than any other crop per unit."[19] This effect can be mitigated by using other materials, such as bamboo and hemp.

Another factor in reusable cloth diaper impact is the ability to re-use the diapers for subsequent children, sale of used diapers through diaperswappers.com[1], craigslist[2] or other online communities, donation of used diapers through recycling groups such as freecycle[3] or to charities such as miraclediapers.org [4]. Many reusable diaper users take advantage of these resources and may even join communities like livejournal's clothdiapering[5] in order to find ways to make their diaper-washing routine more efficient or get feedback about different types of reusable diapers. These factors can alleviate the environmental and financial impact from manufacture, sale and use of brand-new reusable diapers.

Babies may need to have their diapers changed ten or more times a day.[20] Diapering can also serve as a bonding experience for parent and child.[21] To avoid skin irritation, commonly referred to as diaper rash, the diaper of those prone to it should be changed as soon as possible after it is soiled (especially by fecal matter), as feces contain urease which catalyzes the conversion of the urea in urine to ammonia which irritates the skin and can cause painful redness.[22]

The age at which toilet training should begin is a subject of debate and keeping children in diapers beyond infancy can be controversial, with family psychologist John Rosemond claiming it is a "slap to the intelligence of a human being that one would allow baby to continue soiling and wetting himself past age two."[23] Pediatrician T. Berry Brazelton, however, believes that toilet training is the child's choice and has encouraged this view in various commercials for Pampers Size 6, a diaper for older children.[23] Brazelton warns that enforced toilet training can cause serious longterm problems, and that it is the child's decision when to stop wearing diapers, not the parents'.[23][24]

Children may have problems with daytime or more often nocturnal bladder control until eight years or older and need to wear diapers at nighttime to control bedwetting.[25] While awake, most children no longer need diapers when past two to four years of age, depending on culture, diaper type, parental habits, and the child's personality.[26] However, it is becoming increasingly common for children as old as seven to still be wearing diapers because their parents neglect or child's opposition to toilet train. This can pose a number of problems if the child is sent to school wearing diapers, including teasing from classmates and health issues resulting from dirty diapers. Teachers' groups—who are attributing the epidemic to an increase in full-time day care use—are requesting that diapered children be banned from the classroom. The disposable diaper industry has been accused of encouraging this trend by manufacturing diapers in increasingly larger sizes. "[S]uper-comfortable nappies" have also been criticized; the advanced technology in modern diapers wick wetness away from skin, leaving the child oblivious to their accident and when they need to go to the toilet. Paediatric nurse June Rogers claims that the attitude of parents plays a major role in the problem, and that toilet training is simply not a priority for many of them.[27][28][29]

Other countries in which un-potty-trained older children have seen greater mainstream acceptance include Australia, where Queensland news sources report that parents are similarly lax about potty training and have likewise seen increasing numbers of school age children still in diapers.[6]

Because of the increase in older children wearing diapers, diaper manufacturers have designed special "training pants" which bridge the gap between baby diapers and normal underwear during the toilet training process. These training pants are distinct from diapers in that they mimic underwear and do not require complex fastening, so children can be changed standing up or even independently without adult assistance. Studies have shown that the use of training pants instead of diapers can be effective in speeding up toilet training.[30] Larger versions, such as GoodNites, are available for older children and teenagers who have already been toilet trained but continue to suffer from bedwetting. They are intended to be discreet and similar to underwear, so as to avoid alienating those who find wearing diapers at a late age to be embarrassing.[31] Available in both cloth and disposable versions, they are constructed like a diaper with an absorbent core and a waterproof shell and can be worn at any age until the child stops wetting the bed. Because they can be pulled on and off like underpants, children are able to use the toilet if they feel the need, rather than being forced to wet or soil themselves unnecessarily. Whereas most diapers are unisex, training pants often come in sex-specific versions because children become more aware of gender roles as they grow older.[30]

With the development of training pants making it possible for children to change their own diapers, and pediatricians such as Brazelton claiming that forced toilet training can cause lasting psychological and health problems, children are wearing diapers at a much older age than they did historically.[23] The Children's Health and Wellness website claims that diapering a child can prolong bedwetting, as it sends a "message of permission" to urinate in their sleep.[32] Dr Anthony Page of the Creative Child Online Magazine claims that children can get used to their diapers and begin to view them as a comfort, and that of the children surveyed, most would rather wear diapers than worry about getting up at night to go to the toilet.[33] In a series of online surveys, Robert A Pretlow, MD, of eHealth International, Inc., cites an identical figure. He argues that if Internet users are representative of society as a whole, these surveys imply that a fetishistic or emotional attraction to diapers may be responsible for these "comfort" cases, and that "these behaviors are a significant cause of enuresis and incontinence." He called for further studies to be done on the topic.[34]

Parents and other carers for children often carry spare diapers and necessities for diaper changing in a diaper bag.

Although most commonly worn by and associated with babies and children, diapers are also worn by adults for a variety of reasons. In the medical community, they are usually referred to as "adult absorbent briefs" rather than diapers, which are associated with children and may have a negative connotation. People with medical conditions which cause them to suffer from urinary or fecal incontinence may wear diapers or similar products because they are unable to control their bladders or bowels. People who are bedridden or otherwise limited in mobility may also wear diapers because they are unable to access the toilet independently. The usage of adult diapers can be a source of embarrassment,[35] and products are often marketed under euphemisms such as incontinence pads. Some adult diapers have been manufactured in similar design and prints to popular infant diapers for use by infantilists and diaper fetishists.

Diapers and diaperlike products are sometimes used on pets, laboratory animals, or working animals. This is often due to the animal not being housebroken, or for older, sick, or injured pets who have become incontinent. In some cases, these are simply baby diapers with holes cut for the tails to fit through. In other cases, they are diaperlike waste collection devices.

In 2002, the Vienna city council proposed that horses be made to wear diapers to prevent them from defecating in the street. This caused controversy amongst animal rights groups, who claimed that wearing diapers would be uncomfortable for the animals. The campaigners protested by lining the streets wearing diapers themselves, which spelled out the message "Stop pooh bags".[36] In the Kenyan town of Limuru, donkeys were also diapered at the council's behest.[37] A similar scheme in Blackpool ordered that horses be fitted with rubber and plastic diapers to stop them littering the promenade with dung. The council consulted the RSPCA to ensure that the diapers were not harmful to the horses' welfare.[38][39][40]

Other animals that are sometimes diapered include female cats and dogs when ovulating and thus bleeding, and monkeys and apes; most are physically unable to control their excretions, which is not a convenient situation for tree-dwelling animals. Diapers are often seen on trained animals who appear on TV shows, in movies, or for live entertainment or educational appearances.